Holder for a tool blade



April 19, 1955 E. G. BODIN 2,706,327

HOLDER FOR A TOOL BLADE Filed Dec. s. 1955 INVENTOR.

ERIC GUNNAR BODIN /Kui ml 2. HQ,

v ATTORNEY United States Patent Ofiiice 2,706,327 Patented Apr. 19, 1955HOLDER FOR A TOOL BLADE Eric Gunnar Bodin, Karlskoga, Sweden ApplicationDecember 3, 1953, Serial No. 395,908

Claims priority, application Sweden December 5, 1952 14 Claims. (CI.29-96) The present invention relates to a holder for a tool blade,particularly to a holder for a cutting blade used in a lathe.

There are known holders of the general type above referred to, in whichthe holder is formed with a groove receiving the end of the blade.Screws threaded through the bottom of said groove and into the blade endserve to secure the blade in the holder.

Holders of this type are somewhat inconvenient in use as the holes inthe holder and the blade end must be accurately matched before thescrews can be inserted. Furthermore, the number of times a blade can bereground for sharpening is severely limited so that the blade must bediscarded without using the major portion of the blade.

One of the objects of the present invention is to provide a novel andimproved holder for a tool blade such as a cutting blade which permits arapid and convenient attachment and detachment of the blade and whichsecurely holds the blade in position.

Another object of the invention is to provide a novel and improvedholder which permits a regrinding of the blade a far greater number oftimes than convential blade holders thereby allowing a utilization ofthe blade to a much greater extent than heretofore possible.

Still another object is to provide a novel and improved tool holder inwhich the clamping means retaining the blades include a memberconstituting a chip breaker.

Other and further objects, features and advantages of the invention willbe pointed out hereinafter and set forth in the appended claims formingpart of the application.

In the accompanying drawing several now preferred embodiments of theinvention are shown by way of illustration and not by way of limitation.

In the drawing:

Fig. 1 is a sectional view of blade holder according to the invention,and

Fig. 2 is a sectional view of a modification of the blade holder.

Referring first to Fig. 1 in detail, the exemplification of theinvention according to this figure shows a holder comprising a supportmember in which a recess 12 for a blade 2 is formed. This blade may bevisualized as a cutting blade made of a hard metal or tungsten carbide.The support member is further formed with a transverse bore or hole 13disposed near recess 12. A bolt member 14 is fitted axially slidable insaid hole. This bolt member is secured to or integral with a generallyplate-shaped clamping member 3 which together with the bottom of recess12 defines a clamping space for the blade. A loaded spring 6 fittedbetween bolt 14 and the bottom of hole 13 which may be completely closedor shouldered at 15 biases bolt 14 and with it clamping plate 3 in thedirection away from blade 2.

Bolt 14 is formed with a lateral recess 16 in which is extended one armof a two-arm lever 4 pivotal about a pivot point 17. This lever is shownas being disposed within a second recess or hole 18 formed within thesupport member transversely to hole 13. The other arm of lever 4 ends ina slanted bearing surface 19 which coacts with a bearing surface 20 atthe end of a setting device 5. This setting device is shown as a headedscrew threaded into an extension 18' of hole or recess 18.

The holder finally comprises a plate 7 secured to clamping plate 3 forinstance by soldering or integral therewith. This plate is made of avery hard metal or tungsten carbide and serves as a chip breaker.

1 The holder as hereinbefore described, operates as folows:

Let it be assumed that there is no blade fitted in the holder and thatit is desired to insert a blade. For this purpose, screw 5 is screwedout to a certain extent. As a result, the pressure of bearing surface 20upon bearing surface 19 is relieved and spring 6 can push bolt 14 andwith it clamping plate 3 upwardly thereby making space available for theinsertion of a blade in the clamping space defined between the bottom ofrecess 12 and the lower surface of clamping plate 3, the said twosurfaces forming in effect clamping jaws. As is evident, lever 4 ispivoted in clockwise direction when bolt 14 is pushed upwardly as seenin Fig. 1. After a blade has been fitted in recess 12, screw 5 istightened as much as possible. As a result, the pressure of surface 20against surface 19 pivots lever 4 in counterclockwise direction therebypressing the clamping plate 3 against the blade.

The blade holder according to Fig. 2 is similar in principle to theblade holder according to Fig. 1. Accordingly, corresponding parts aredesignated by the same reference numerals though primed.

The arrangement of the lever and the setting device are the same as inFig. 1 with the exception that the screw head of Fig. 1 is replaced by athreaded bore. According to Fig. 2, a bolt member 8 is fitted axiallyslidable in transverse hole 13. The bolt ends in a setoff stub 8' uponwhich clamping plate 3' and the chip breaking plate 7 secured to plate 3are rotatably fitted. Plates 3' and 7 can be tightly clamped to bolt 8by tightening a lock nut 11. The adjustability of the angular positionof plate 7 relative to bolt 8 and hence also relative to blade 2 permitsto set the chip breaker for an angle best suited to the cut for whichthe blade has been designed or set.

Support member 1 is formed with a second transverse hole or bore 21disposed parallel to bore 13 and opening in the bottom of recess 12. Abolt 9 is inserted in bore or hole 21 so that the bolt is axiallydisplaceable but preferably secured against rotation. The end of bolt 9is formed with or is secured to a slanted bearing surface 22. Thisbearing surface is so positioned that it is engageable with the inneredge of a blade 2 inserted in the holder. A screw 10 threaded in bore orhole 21 serves to position bolt 9 within the hole and to move theslanted surface 22 into the clamping space defined between clampingplate 3 and the bottom of recess 12.

The operation of the holder according to Fig. 2 is as follows:

The insertion of a blade in the holder and the tightening of the bladetherein are apparent from the description of Fig. 1.

Let it now be assumed that the blade has been reground one or severaltimes so that its rear edge will no longer bear against the rear endwall of the recess, Fig. 1 showing the blade bearing against the saidend wall. As a result, a gap is left between the rear edge of the bladeand the end wall of the recess resulting in g ciarresponding loss of theclamping support for the la e.

The arrangement of Fig. 2 permits to compensate for the reduction in thelength of the blade end by tightening screw 10 whereby the slantedsurface 22 is forced to abut against the rear edge of the blade thusefiectively preventing a rearward displacement of the blade within therecess.

As appears from the previous description, bolt 9 and its slanted surface22 permit a compensation of variations of the blade length in the holderwithin wide limits. can be used to the fullest extent and also thatblades having different lengths can be inserted in the same holder.

While the invention has been described in detail with respect to certainnow preferred examples and embodiments of the invention it will beunderstood by those This has the advantage that a cutting blade skilledin the art after understanding the invention, that various changes andmodifications may be made without departing from the spirit and scope ofthe invention, and it is intended, therefore, to cover all such changesand modifications in the appended claims.

What is claimed as new and desired to be secured by Letters Patent, is:

1. A holder for a tool blade comprising a blade support member, clampingmeans for releasably clamping the blade between said support member andsaid clamping means, said support member having a hole therethrough, abolt member secured to the clamping means and slidably fitted in saidhole for displacement of the clamping means in unison with the boltmember, a twoarm lever pivotally supported by said support member, onearm of said lever operatively engaging said bolt member for axialdisplacement thereof, and an adjustable setting means coacting with theother arm of said lever for pivoting the lever and retaining the sameand said bolt member in a position in which a blade is clamped betweenthe clamping means and the support member.

2. A holder according to claim 1, wherein said support member has asecond hole issuing in the first hole transversely thereto, and whereinthe said two-arm lever is pivotally mounted within said second hole, thesaid setting means being operable from the outside of said supportmember.

3. A holder according to claim 1 and further comprising loaded yieldablemeans disposed within said hole and biasing the bolt member in thedirection for moving the clamping means away from the support member.

4. A device according to claim 1, wherein the said setting means and therespective arm of the two-arm lever each has a bearing surface, the saidbearing surfaces coacting with each other so as to effect pivoting ofsaid lever upon adjustment of said setting means.

5. A holder according to claim 4, wherein the said coacting bearingsurfaces are in form of slanted surfaces in engagement with each other,and wherein the said setting means are adjustable for varying thedistance between the pivot point of said lever and the setting meansthereby effecting pivoting of the lever by varying said distance.

6. A holder according to claim 5, wherein the said support memberincludes a second hole issuing in the first hole transversely thereto,the said two-arm lever being pivotally mounted within said second hole,and wherein the said setting means comprise a screw member threaded insaid support member and protruding into said second hole, the inner endof said screw member forming the respective slanted bearing surface.

7. A holder according to claim 1, wherein the bolt member is rotatablewithin said hole, and wherein the said clamping means comprise aplate-shaped member secured to the bolt member for rotation in unisontherewith relative to the support member, the said plateshaped memberand a respective outer surface of the support member forming two jawsfor clamping the blade therebetween.

8. A holder according to claim 7, wherein the said plate-shaped memberhas a portion made of very hard metal and shaped to form a chip breaker.

9. A holder according to claim 8, wherein the said bolt member is formedwith a stub protruding from the support member, the said plate-shapedmember being rotatably fitted upon said stub, and wherein a locking nutis provided for securing the plate-shaped member on said stub in aselected angular position relative to the support member.

10. A holder according to claim 1, wherein the said support member has asecond hole therethrough disposed parallel to the first hole, andwherein a second bolt member is fitted in said second hole axiallyadjustable therein, one end of said second bolt member forming a bearingsurface positioned to abut against the inner dge of a blade clamped inthe clamping space defined between said clamping means and said supportmember.

11. A holder according to claim 10, wherein said bearing surface of thesecond bolt member extends into said clamping space and is slanted so asto form an abutment for the inner edge of a clamped blade for preventingdisplacement of the blade within said clamping space.

12. A holder according to claim 11 and further comprising a secondsetting means coacting with the other end of said second bolt member forvarying the axial position of said second bolt member in its holethereby correspondingly varying said clamping space.

13. A holder according to claim 12, wherein the said second settingmeans comprise a screw member threaded in said support member on theside thereof opposite to the clamping space.

14. A holder according to claim 13, wherein the said second bolt memberis secured against rotation within its hole.

References Cited in the file of this patent UNITED STATES PATENTS2,062,607 Reaney Dec. 1, 1936 2,063,129 Severson Dec. 8, 1936 2,357,918Trippler Sept. 12, 1944 2,583,880 Premo Jan. 29, 1952 FOREIGN PATENTS309,007 Germany Nov. 9, 1918 607,417 Great Britain Aug. 31, 1948 968,404France Nov. 27, 1950

